The inhibitory effects of MIP-α on BFU-E formation from CD34⁺ BM cells was partially abrogated by anti-CCR1 antibodies. Purified CD34⁺ BMMNCs were plated in a methylcellulose medium containing Epo and SCF with (solid bar) or without (open bar) recombinant human MIP-α, or a combination of the growth factors and recombinant human MIP-α with the indicated doses of anti-CCR1 antibodies (diamond bar) or control antibodies (square bar). The number of BFU-E was determined at day 14 of culture. The data are representative of three independent experiments with quadruplicate determinations. * Indicates significant difference from control culture without anti-CCR1 antibody by using one-way ANOVA analysis and multiple comparison by Fisher's method.